The (tracer) diffusion coefficient D has been measured by Mundy in Na, for various pressures up to 9.46 kbar, at T = 288 K. The plot In D versus P showed a strong curvature, which has been previously attributed to the coexistence of various diffusion mechanisms. By following the theory described in the accompanying paper, we calculate the local com-pressibility~',of a single vacancy and we find that it exceeds the bulk one by a factor of 2-3.Therefore an important factor of the form exp Ji d d P has possibly been disregarded in the previous analysis of the curve In D versus P. Considering the correction introduced by such a factor, we confirm that the curvature in the isothermal plot In D versus P is exclusively due to the vacancy high local compressibility, over all the pressure range. Our mean x'-value, calculated only from bulk properties, is in striking agreement with a recent analysis made by Gilder and Lazarus.